Install fails with Integrity Constraint Violation on key identifier

WD php: PDOException: SQLSTATE[23000]: Integrity constraint
violation: 1062 Duplicate entry '' for key 'identifier': INSERT INTO
{field_group} (group_name, entity_type, bundle, mode, parent_name,
data) VALUES (:db_insert_placeholder_0, :db_insert_placeholder_1,
:db_insert_placeholder_2, :db_insert_placeholder_3,
:db_insert_placeholder_4, :db_insert_placeholder_5); Array

I get this on install of field_group onto a site that had cck fieldgroups in d6. The problem is that the schema gets made with the identifier column, but then the ctools_export_crud_save calls don't populate identifier. Patch attached fixed it for me.